Hello there. To solve this question, we have to remember some properties about conversion of values.
1. How many 2-liter bottles of soda will you need to fill ten 500 mililiter containers?
First, multiply the number of containers by its capacity, that is

Notice that 1000 mililiters is equivalent to 1 liter, hence

To fill these containers with 2-liter bottles of soda, you'll need at least 3 bottles.
The answer to the first question is 3.
2. How many mililiter are 1/5 liter?
Considering 1 liter = 1000 mililiters, we have that

Hence the answer to this question is 2. 200